C# asp.net服务器端如何 输出json格式的数据

Response.ContentType = "text/xml";
        Response.Write(" <?xml version='1.0' encoding='utf-8'?>");
        Response.Write(" <test>");
        Response.Write(" <com>");
        Response.Write(" <code>" + areader3.GetInt32(0).ToString() + " </code>");
        Response.Write(" <name>" + areader3.GetString(1) + " </name>");
        Response.Write(" <ext>" + areader3.GetString(2) + " </ext>");
        Response.Write(" </com>");
        Response.Write(" </test>");

xml格式的可以这样输出  那要输出json格式的该怎么写

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Response.ContentType = "text/plain";
Response.Write("[{\"name\":\"a\"},{\"name\":\"b\"}]");

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Response.ContentType = "text/xml";
Response.Charset = "UTF-8";
System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
doc.LoadXml(strXML);
doc.Save(Response.OutputStream);
Response.End();

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context.Response.ContentType = "text/plain";
          var orders;